I think it's a possibility that the current Days writers would have Carly being pregnant with Bo's child when she left for Paris with Lawrence 16 years ago.

They would be re-writing history, though, because one of the factors that undermined Bo & Carly's relationship before she left was the fact that Carly couldn't have children because of something that happened with Nikki's birth. Knowing that she could never have Bo's child made her connection to Lawrence through their child together all the more powerful.